1. Field of the Invention
This invention relates to solid-state relays in general and, more particularly, to solid-state relays with multiple sections, such as single-pole, double-throw (Form C) relays.
2. Description of the Prior Art
The reliability, speed, quietness, and efficiency of solid-state relays make them an attractive alternative to mechanical (electromechanically operated) relays. As a result, solid-state relays have significantly displaced mechanical relays in low and medium power applications. More particularly, both normally-open (form A) and normally-closed (form B) single pole relays have found wide application. However, single-pole, double-throw (SPDT or form C) solid-state relays have not found wide application to date, compared to their mechanical equivalent. One advantage of the form C mechanical relay over the form C solid-state relay is the mechanical relay's ability to be configured to operate reliably as either make-before-break or break-before-make. Similarly, double (or more) form A or form B solid-state relays whose sections operate in delayed synchronism are also difficult manufacture with reliable section timing.
A major reason for the form C (or multisection form A or multisection form B) solid-state relay's inability to operate reliably as a break-before-make (or make-before-break) relay is the difficulty of reliably delaying the operation of one section of the relay with respect to the other section(s) thereof.